Wishbone cross-arm construction for transmission-poles



L. M. KLAUBER.

WISHBONE CROSS ARM CONSTRUCTION FOR TRANSMISSION POLES.

APPLICATION FILED SEPT. H, I919.

1,359,509, Patented Nov. 23, 1920.

2 SHEETS-SHEET I.

L. M. KLAU BER.

WISHBONE CROSS ARM CONSTRUCTION FOR TRANSMISSION POLES- APPLICATION FILED SEPT. II, 1919.

Patented Nov. 23, 1920.

2 SHEETS-SHEET 2.

it venir UNITED STATES PATENT OFFICE.

LAURENCE M. KLAUBER, OF SAN DIEGO,

CALIFORNIA, ASSIGNOR OF ONE-HALF T0 SAN DIEGO CONSOLIDATED GAS & ELECTRIC COMPANY, OF SAN DIEGO, CALIFOR- NIA, A CORPORATION OF CALIFORNIA.

Specification of Letters Patent.

Patented N 0V. 23, 1920.

Application filed September 11, 1919. Serial No. 323,139.

To all whom it may concern: h

Be it known that I, LAURENCE M. KLAUBER, a citizen of the United States, residing in the county of San Diego, city of San Diego, and State of California, have invented new and useful Improvements in Wishbone Cross-Arm Construction for Transmission- Poles, of which the following is a specification.

This invention relates to the overhead construction for poles carrying high-tension transmission lines, and especially to what is known as the Wishbone type of construction, in which two cross-arms are employed, attached to the pole at dilferent points and connected rigidly at their ends. This construction is advantageous because it provides three widely separated points of support for three transmission lines and also gets the elicct of an increased height for the pole. It also avoids the necessity for employing individual braces for the arms, thereby reducing the cost of the construction. It is desirable in such a construction that the ends of the arms should overlap each other at the point where they are connected together, but, if it is attempted to produce this construction by attaching the cross-arms to thepole in different planes and on parallel faces or arm seats cut in the side of the pole, it becomes necessary to cut one of the gains to a relatively great depth, that is to say, one of the gains must have a depth greater than the other by an amount equal to the thickness of the cross-arm. This great depth for the gain is not desirable because such deep gains are cut with difliculty and they also increase the cost of the pole. Furthermore, they weaken the pole considerably on account of the reduction in crosssection which results from their use. In transmission lines and in telegraph lines it is customary to attach the cross-arms alternately on the front sides and the rear sides of the poles, for the reason that with that arrangement tension in the line is resisted in both directions. On account of this practice, if it were attempted to produce the cross-arm construction with overlapping parallel arms, as suggested above, it becomes necessary to form two classes of poles, one with the gain slanting one way, and the other with the gain slanting the other way.

The general object of the present invention is to overcome these difficulties, and to provide a reversible wishbone cross-arm construction which Wlll enable poles having the same kind of notches or gains to be used for constructing all the transmission poles for the line, that is to say, I produce a type of ,pole in which I avoid the use of an unusually deep gain and to which the crossarms can be attached either on the front of the pole, or on the back of the pole, so that when all the poles are erected, they will match up with each other to suspend the transmission lines and will have the crossarms alternately on the front and rear sides 0f the poles, in the regular way.

The invention consists in the novel means and in the general combination of parts to be particularly described hereinafter, all of .which contribute to produce a simple and eflicient wishbone construction for transmission lines. A preferred embodiment of my invention will be particularly described in the following specification, while the broad scope of my invention will be pointed out in the appended claims.

In the drawing,

Figure 1 is a front elevation of a pole having the wishbone cross-arm construction embodying my invention;

Fig. 2 is a View similar to Fig. 1 showing a similar type of pole which is used to co- %perate with the poles of the type shown in Fig. 3 is a view similar to Fig. 1, but representing the pole of the type illustrated in Fig. 2 in a reversed position, that is to say, it

represents the pole of Fig. 2, rotated on its vertical axis through 180 degrees;

Fig. 4 is aplan broken away and indicating the approved manner suggested above consisting in alternating the position of the arms on the poles in line construction;

Fig. 5 is a side elevation showing the overlapping ends of two cross-arms, and illustrating details of my invention;

Fig. 6 is a section taken through Fig. 5 on the line 6-6; and

Fig. 7 is a plan of the pole, and particularly illustrating the relation of the gains to each other.

Referring especially to Fig. 1, A represents the upper end of a pole carrying two cross arms a and a. The cross-arm a is attached to the pole at a horizontally cut gain, or notch 1, which is cut in a. vertical plane 'atright angles to the transverse axial line 2 of the pole, which extends in the direction in which the line wires are strung, (see Fig. 7 Above the gain 1, on the same side of the pole and at the end of the pole I provide an upper gain 3 having a vertical face which is disposed in a plane forming an angle with the vertical face of the gain 1, and the planes of the vertical faces of these two gains intersect each other near axial line 2, that is to say, in the middle plane of the pole extending in the stringing direction. Now when the arm a is attached to the gain 3, by means of a suitable bolt 4, it should be secured with its right-hand end.

depressed as shown in Fig. 1, so that the ends of the two cross-arms a and a. overlap each other.

\Vhen these arms overlapin this way, it

should be understood that the adjacent faces of the arms will not lie flush against each other, in fact, the gain 8. is so placed that a space orgap will be formed between the overlapping ends of the arms. In this space, I provide a bracket 5, (see Figs. 5 andfi), which bracket is preferably in the form of a tapered filler or wedge plate, that is to say, it is of varying thickness, being narrow toward its inner and upward edges, and thicker toward its lower and outer edges. This plate may be of skeleton form (see Fig. 5), and provided with openings 6 which reduce the weight of metal in the plate. i

In order to enable the bracket or filler plate 5 to engage securely with the adjacent faces of the overlapping arms aand a, I provide the faces of the plate with projectionsor spurs 7 which penetrate the wood of the arms and greatly increase the rigidity of the connection. I also provide clamping means for clamping the two arms together and against the intervening filler plate. This clamping means is'preferably simply a through bolt 8 which passes through a suitable opening 9 in a bridge bar 10 extending across the plate.

Having attached the cross-arms together in this way, they are then ready to receive the suspension insulators llcarrying the conductors 12.

Referring to Fig. 4, it will be noted that the alternating poles A have their cross arms attached in the manner described. I shall. now describe the manner of producing the intermediate poles B which are disposed between the poles A.

In this connection it will be noted that the poles B' have their cross-arms attached produce one of the R type poles, (see Fig;

2.) it issimply necessary to attach the left.-

the lower arm Z) on its rear face in F 1g. 2, instead of on the front face as in.

the case of the A-type of pole. And also by reason of the symmetrical location ofthe gain 3, a space will be formed between the overlapping ends of the arms I) and Z), ex-

actly similar to the space formed between the two arms a and a Hence the construction is a reversible cross-arm construe tion, that is to say, the same size and form of bracket or filler plate can be interposed between the adjacent faces of the arms 7; and b, and thearms can be secured together in thesaine way as the arms a and'a', by means of a suitable through bolt 8.

Now if the pole constructed as shown in Fig. 2 is reversed, or rotated on its longitudinal axis through 180 degrees,.tl1e parts will come into the relation shown in Fig. 3. From an inspection of this figure, it will be noted that the arm Z) will then be parallel with the arm a, but the arms Z) and 7) are located on the back of the pole instead of on the front as is the case in the pole A shown in Fig. 1. Hence it is evident that the poles B can be planted alternately with the poles A, and will cooperate with them to support the three transmission lines 12. hurthermore, it will be evident that by reason of the location of the arms of the poles B with relation to the arms of the poles A, I obtain the effect of the alternate front and rear attachment of the arms referred to above as being a necessary feature of such a-line construction.

Although I have illustrated both types of poles with the upper arms attached by a single bolt, it is evident that, if desired, additional fastening means can be employed for fastening either or both cross-arms to the poles.

It will be evident that the wishbone crossarm construction described above will a very rigid self-bracing structure. I

I have found it practicable to have the angle between the planes of the vertical faces of the gains about five degrees. But this angle depends, of course, upon the length of the arms and the thickness desired for the filler plates. A rough pattern of the filler plate suflicient to determine the thicknesses for the filler plate, is very easily formed by filling the space or gap between the ends of the cross-arms with plaster of Paris and permitting it to harden while in place.

give

It is understood that the embodiment of the invention described herein, is only one of the many embodiments my invention may take, and I do not wish to be limited in the practice of my invention nor in my claims to the particular embodiment set forth.

What I claim and desire to secure by Let ters Patent is:

1. In a reversible wishbone cross-arm construction, the combination of a pole, a crossarm attached to the pole, a second cross-arm attached to the pole on the same side as the first named cross-arm, and in a plane forming an angle with the plane of the first named cross-arm, said arms overlapping at their ends so as to form a space between the adjacent side faces of the arms at the overlapping point, a tapered filler plate disposed in the space between the overlapped ends of the arms, having means for engaging the adjacent faces of the arms, and a bolt passing through the arms and the filler plate and clamping the same together.

2. In a reversible wishbone cross-arm construction, the combination of a pole, a horizontal cross-arm, said pole having a gain cut therein having a Vertical face to form a seat for a second cross-arm, said vertical face being on the same side of the pole as said cross-arm, and disposed at a slight angle to the plane of the first named cross-arm, whereby the second cross-arm may be attached to the pole at said gain, with either end overlapping one of the ends of the first named cross-arm.

3. A member for connecting cross-arms in a reversible wishbone cross-arm construction, consisting of a plate of varying thickness, and having means projecting from its faces for engaging the cross-arms.

4:. A member for connecting the crossarms in a reversible wishbone cross-arm construction, consisting of a plate of wedge form having spurs on its opposite side faces for engaging the cross-arms and having an opening therethrough to receive a clamping bolt.

5. In a reversible wishbone cross-arm construction, the combination of a pole, a horizontal cross-arm attached to the pole, a second cross-arm on the same side as the first named cross-arm and in a plane forming an angle with the plane of the first named cross" arm, said last-named cross-arm operating to overlap the end of the first named crossarm when the second named cross-arm is held with either of its ends depressed, a wedge-form member adapted to be received in the space between the overlapped ends of the cross-arms, and means for clamping the overlapped ends of the arms together against said member.

In testimony whereof I have hereunto set my hand.

LAURENCE M. KLAUBER. 

